Switching devices are well known in principle. They are used as protection for electrical circuitry whereby pole terminals of the switching device are separated from one another in the event of an overload. The breaking of this electrical connection serves to prevent damage to components and devices disposed in the electrical circuit. For this purpose known switching devices often have a switching mechanism of rotary design. The rotatable switching arms of such a switching mechanism can connect and disconnect a fixed contact and a movable contact. Redundancy is often provided, so that a double arm can be brought into contact with two corresponding fixed contacts on both sides of an axis of rotation as a movable contact.
The disadvantage of known switching devices is that, when the contacts are opened in the event of an overload, an arc is often generated. This arc causes gas to be produced which must leave the switching chamber of the switching mechanism.
In known switching devices, a duct implemented in the enclosure or in the pole cassette is basically provided for this purpose. The gas produced by the arc during the switching process can leave the switching chamber via this duct. However, in the case of known switching devices such as those disclosed in U.S. Pat. No. 6,480,082 B1, for example, protection of the electrical components of the switching device is unknown. Thus the danger there is basically that the gas, which is not or only inadequately discharged, will cause contamination inside the switching chamber, particularly in the vicinity of electrical components.
If, for example, a duct is provided in the switching device enclosure, this enclosure duct must be sealed to the switching chamber. The danger of this seal as a predetermined fracture point at the high switching pressures is that gas and therefore contamination will impair electrical components for controlling the switching device. As this fouling is mainly electrically conductive contamination, this may result in undesirable short circuit situations in the electrical components and therefore damage or even destruction of the switching device.